Research On Position And Heading Control Technology Of The Unmanned Helicopter During Hover Flight

Hover flight is very unique and also one of the most important flying abilities of unmmaned helicopters. Basic flying functions have been fulfilled by using primary control strategies. However, the performance cannot be satisfactory. Thus this thesis aims at several desiderating problems and presents advanced control strategies.Firstly, aming at the lack of dependable and convenient mathematical model, this thesis studies Rotorlib modeling method. Then reduces the rank of its high order linearized model and analyses the characteristics of the sample UAV. The model lays a foundation for the control law design and simulation.Secondly, aming at the lack of position accuracy in the atmospheric disturbance, a ground-speed-based control scheme is presented. Two kinds of hover modes can be obtained by using this scheme: ground-speed hover and position hover based on ground-speed. The scheme suits the needs of different hover situations and higher position accuracy can be obtained by position hover based on ground-speed. An advanced heading control law is designed based on attitude command in-loop because of the poor adaptability of primary control strategy. Yaw rate control is the core of this scheme, which conforms to the characteristics of the UMH. Heading-keeping comparative analysis indicates that the advanced control law has a stronger ability to endure disturbance. And the stability of heading channel can be improved.Furthermore, in order to verify the control law rapidly, an equivalent simulation environment is developed. And this thesis focuses on the equivalent flight control software and the simulation model software. Equivalent flight control software uses the Windows version of ?cos-II, which ensures the navigation control module is completely consistent with real flight control software. The simulation software is based on the repackaging of Rotor Lib model and makes it more convenient.Finally, comprehensive comparisons are implemented to verify the control laws. Simulation indicates that advanced control strategies improve the flight performance. Flight test also proves the feasibility of the control laws designed in this thesis.